Mars’ Soil is Another Strike Against Life as We Know It

Mars is a barren, cold wasteland. But, it’s also the closest planet to home. And the easiest place to hunt for answers to the ultimate science question. Are we alone in the universe?

Life faces extreme challenges of existing on Mars today. The temperature, lack of water and constant bombardment of radiation through its thin atmosphere all work against even the smallest bacteria. Today, scientists are adding another problem to the equation. The soil.

Sorry Mark, those potatoes on Earth wouldn’t work with Martian soil.

The new problem stems from chemical compounds called perchlorates found on the red planet’s surface. When exposed to UV light, the chemicals become deadly to Earth-based bacteria.

This effect is even more pronounced when you toss in two other chemicals found on Mars’ surface – iron oxides and hydrogen peroxide. Experiments conducted with all three present increased the death of bacterial cells 10-fold compared to just perchlorates.

Here are the scientists on what this means. From the paper: “These data show that the combined effects of at least three components of the Martian surface, activated by surface photochemistry, render the present-day surface more uninhabitable than previously thought, and demonstrate the low probability of survival of biological contaminants released from robotic and human exploration missions.”

That last line is interesting. If this data is correct, contamination from human missions would be slim. NASA already has safeguards in place to help protect life on other planets and moons with their Planetary Protection requirements. But if Mars’ environment kills off Earth-based life forms, NASA could expand on where they want to land future missions. That’s a big ‘if,’ but it is interesting.

“Our findings have important implications for the possible contamination of Mars with bacteria and other materials from space missions. This should be taken into account in designing missions to Mars,” says the paper’s author Jennifer Wadsworth.

This isn’t the end of the search for life on the red planet. What about beneath the surface where UV light’s interaction with surface chemicals doesn’t happen? We know plenty about today’s Mars. It’s the planet’s distant past that could hold the answer to the ‘are we alone’ question.

Plus, this new data shows how Mars’ environment reacts to Earth-based life. Bacteria on Mars could be different. We just don’t know. NASA’s rovers do a fantastic job exploring the surface, but definitive answers won’t come until space boots are on the ground.

One thing is for sure. The first Martian explorers better bring their own dirt if they plan on planting potatoes.